JP2002-14487 A discloses a technique of a toner prepared by adding an external additive containing a positively chargeable silica and a negatively chargeable silica to a toner matrix containing a fluorine-containing polymer, a polyester and a colorant, whereby the aggregation of the toner particles themselves can be suppressed, and image properties can be stabilized upon continuous use under low-humidity, low-temperature conditions.
JP-A-Hei-11-202551 discloses a technique relating to a process for preparing a color toner including the steps of pulverizing a mixture of a melt-kneaded mixture containing a resin binder, a wax and an organic chromatic colorant with fine inorganic oxide particles, and classifying the resulting pulverized product, whereby the feed of a releasing agent to a heat roller can be made as little as possible, thereby obtaining excellent color fixed images.